BACKGROUND: The objective of this study was to estimate the risk of severe osteoarthritis, with the need for arthroplasty, in the knee and/or hip according to body mass index (BMI) both within a normal range and in persons with high BMI. Furthermore, we wanted to study the significance of smoking. METHODS: This study identifies male construction workers participating in a national health control program (n = 320,192). The incidence rate for joint replacement was found by matching with the Swedish hospital discharge register between 1987 and 1998. BMI and smoking habit was registered at the time of the health examination. RESULTS: In total 1495 cases of osteoarthritis of the hip and 502 cases of osteoarthritis of the knee were identified and included in this analysis. The incidence rate was found to increase linearly to the BMI even within low and 'normal' BMI. The relative risk for osteoarthritis of the hip was more than two times higher in persons with a BMI of 20-24 than in men with a BMI 17-19. There was almost a doubling of the risk of severe knee osteoarthritis with an increase in BMI of 5 kg/m2. Smoker had a lower risk of osteoarthritis than non-smokers and ex-smokers. CONCLUSIONS: BMI is an important predictor of osteoarthritis even within normal BMI. A decreased risk of osteoarthritis of the hip was found in smokers, but the effect was weak compared to that of BMI or age. Contrary to studies of radiographic osteoarthritis our study indicates higher risk of hip than of knee osteoarthritis.
In geographical studies, population distribution is a key issue. An unequal distribution across units of analysis might entail extra-variation and produce misleading conclusions on healthcare performance variations. This article aims at assessing the impact of building more homogeneous units of analysis in the estimation of systematic variation in three countries.
Hospital discharges for six conditions (congestive heart failure, short-term complications of diabetes, hip fracture, knee replacement, prostatectomy in prostate cancer and percutaneous coronary intervention) produced in Denmark, England and Portugal in 2008 and 2009 were allocated to both original geographical units and new ad hoc areas. New areas were built using Ward's minimum variance methods. The impact of the new areas on variability was assessed using Kernel distribution curves and different statistic of variation such as Extremal Quotient, Interquartile Interval ratio, Systematic Component of Variation and Empirical Bayes statistic.
Ward's method reduced the number of areas, allowing a more homogeneous population distribution, yet 20% of the areas in Portugal exhibited less than 100 000 inhabitants vs. 7% in Denmark and 5% in England. Point estimates for Extremal Quotient and Interquartile Interval Ratio were lower in the three countries, particularly in less prevalent conditions. In turn, the Systematic Component of Variation and Empirical Bayes statistic were slightly lower in more prevalent conditions.
Building new geographical areas produced a reduction of the variation in hospitalization rates in several prevalent conditions mitigating random noise, particularly in the smallest areas and allowing a sounder interpretation of the variation across countries.
Division of Rheumatology, Department of Medicine, Women's College Hospital, 76 Grenville Street, 8th Floor, Room 815, Toronto, ON M5S 1B2, Canada. g.hawker@utoronto.ca
The role of knee arthroscopy in the management of osteoarthritis is unclear. The purpose of this study was to examine patterns of use of knee arthroscopy, overall and by diagnostic and sociodemographic subgroups, in countries with comparable health-care systems.
Administrative databases were used to construct cohorts of adults, twenty years of age or older, who had undergone their first knee arthroscopy in 1993, 1997, 2002, or 2004 either in Ontario, Canada, or in England. For each year, age and sex-standardized rates of knee arthroscopy per 100,000 population were determined overall and by diagnosis, sex, age, and income quintile. Regression analysis, with control for confounders, was used to examine predictors of readmission for primary total knee replacement up to five years after an index knee arthroscopy performed in 1993 or 1997. We also analyzed the records of patients who had undergone primary knee replacement in 2002 to determine the rates of knee arthroscopy in the two years prior to that replacement.
In both countries, the proportion of arthroscopic procedures performed to treat internal derangement or dislocation of the knee increased over time; the rates were highest in the highest income quintiles. The study revealed that 4.8% of the patients in England and 8.5% of those in Ontario who had an arthroscopy to treat osteoarthritis in 1997 received a knee replacement within one year after that procedure. The risk of readmission for knee replacement was greater in association with a diagnosis of osteoarthritis, female sex, and an older age at the time of the arthroscopy. Of the patients who had a primary knee replacement in 2002, 2.7% in England and 5.7% in Ontario had undergone a knee arthroscopy in the previous year; the likelihood of the patient having had a prior arthroscopy increased with higher income and increasing age.
Variations in knee arthroscopy rates according to age, sex, income, and diagnosis were identified in both countries. Research to determine if these differences are consistent with need is warranted.
Past incidence and future demand for knee arthroplasty in Sweden: a report from the Swedish Knee Arthroplasty Register regarding the effect of past and future population changes on the number of arthroplasties performed.
By combining data from the Swedish Knee Arthroplasty Register and Swedish census registers we have calculated the past age-specific incidence of primary knee arthroplasties and predicted the demand. During the last 20 years, osteoarthrosis has accounted for the largest increase in number of knee arthroplasties while operations for rheumatoid arthritis remained constant. The mean yearly number of operations between the periods 1976-1980 and 1996-1997 increased more than five-fold, while only 6% of that increase could be explained by changes in the age-profile of the population. Most operations were performed on persons of 65 years and older who also had the largest increase in incidence. By using the incidences for 1996 and 1997 and taking into account the expected future changes in the age profile of the Swedish population, we estimate that, in the absence of an effective preventive treatment, the number of knee arthroplasties will increase by at least one third until 2030.
To examine prospectively the predictors of time to total joint arthroplasty (TJA).
This was a prospective cohort study with a median followup time of 6.1 years. We included participants from an existing population-based cohort of 2,128 individuals, ages 55 years and older with disabling hip and/or knee arthritis and no prior TJA, from 2 regions of Ontario, Canada, 1 urban with low TJA rates and 1 rural with high rates. The main outcome measure was the occurrence of a TJA based on procedure codes in the hospital discharge abstract database.
At baseline, the mean age of the patients was 71.5 years, 67.9% had a high school education or higher, 73.4% were women, the mean arthritis severity (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) score was 41.1 (maximum possible score 100), and 20.0% were willing to consider TJA. Greater probability of undergoing TJA was associated with higher (worse) baseline WOMAC scores (hazard ratio [HR] 1.22 per 10-unit increase, P or=82 years; P
To determine the relationship between regional variations in knee replacement (KR) utilization rates in Ontario, Canada, and the reported prevalence of arthritis and rheumatism as a chronic health problem.
Utilization data were acquired from the Canadian Institute for Health Information for KR procedures performed in Ontario between fiscal years 1984 and 1990. Census information was obtained from Statistics Canada. Disease prevalence data were derived from the 1990 Ontario Health Survey (OHS). Public Health Units (PHU) were used as the unit of analysis, with utilization rates defined as the number of KR performed on all PHU residents (irrespective of where these procedures were performed) divided by the population. Direct methods were used to standardize utilization for age, sex, and disease prevalence. The extremal quotient, the weighted coefficient of variation, and the systematic component of variation were used as measures of variation. The relationship between the number of KR performed in each age-sex-year strata and various demographic (age and sex), disease prevalence, and regional dummy variables was estimated using a Poisson regression model.
Regional variation in the standardized utilization of KR surgery was wide, but declined over the study period; the extremal quotient fell from 8.0 to 3.3, the weighted coefficient of variation fell from 0.49 to 0.30, and the systematic component of variation fell from 0.20 to 0.17. Variation in the provision of KR surgery remained even after controlling for the demographic composition of the population and disease prevalence. Moreover, while demographic, regional, and temporal covariates were significant (p 0.05).
This study merged population based reports of disease prevalence with administrative data to account for regional variations in utilization. While regional variations in KR surgery have fallen over time, variations remain even after adjusting for patient reported disease prevalence. The finding that demographic variables and the reported prevalence of disease were poorly correlated suggests that current area variation studies may not be adjusting fully for disease prevalence or severity.
The question of how best to reduce waiting times for health care, particularly surgical procedures such as hip and knee replacements is among the most pressing concern of the Canadian health care system. The objective of this study was to test the hypothesis that significant seasonal variation exists in the performance of hip and knee replacement surgery in the province of Ontario.
We performed a retrospective, cross-sectional time series analysis examining all hip and knee replacement surgeries in people over the age of 65 in the province of Ontario, Canada between 1992 and 2002. The main outcome measure was monthly hospitalization rates per 100,000 population for all hip and knee replacements.
There was a marked increase in the rate of hip and knee replacement surgery over the 10-year period as well as an increasing seasonal variation in surgeries. Highly significant (Fisher Kappa = 16.05, p
The Western Canada Waiting List Project (WCWL) is a federally funded initiative designed to develop tools for managing waiting lists. The principal tools developed by WCWL are point-count measures that assess the severity of patients' conditions and the extent of benefit expected from wait-listed services. Points are assigned according to the severity of patients' symptoms and clinical findings. Points on each factor are added and the total score is considered indicative of relative clinical urgency. Such point-count measures function as linear models from a statistical perspective. This paper describes the relevance of this functional relationship for the development and validation of priority criteria.
Stable occurrence of knee and hip total joint replacement in Central Finland between 1986 and 2003: an indication of improved long-term outcomes of rheumatoid arthritis.
Total joint replacement (TJR) surgery is an important severe long-term outcome of rheumatoid arthritis, but relatively little is known about changes of its incidence in patients with rheumatoid arthritis over the past two decades.
A population-based, retrospective, incidence case review was conducted to analyse the frequency of primary TJR surgery of the knee and hip in all patients, and specifically in patients with rheumatoid arthritis in Central Finland between 1986 and 2003. Patients with TJR surgery of the knee and hip were identified in hospital databases over the 18-year period. Age-standardised incidence rate ratios for the primary TJR of the knee and hip were calculated, stratified to sex and diagnosis, with 1986 as the reference value.
In patients without rheumatoid arthritis the age-adjusted incidence rate ratios (with 95% CI) for TJR of the knee increased 9.8-fold from 1986 to 2003 in women and men, and for TJR of the hip 1.8-fold in women and 2-fold in men. By contrast, no meaningful change was seen over this period, in age-adjusted incidence rate ratios for TJR of the knee or hip in patients with rheumatoid arthritis, ranging from 0.7 to 1.2 in 2003 compared with 1986.
The prevalence of TJR surgery has increased 2-10-fold in patients without rheumatoid arthritis patients, associated with an ageing population, but has not increased in patients with rheumatoid arthritis between 1986 and 2003. These data are consistent with emerging evidence that long-term outcomes of rheumatoid arthritis have improved substantially, even before the availability of biological agents.
The demand for total hip and total knee arthroplasties is increasing as are the waiting times for these procedures. Because of the differences between rural and urban areas in terms of the provision of arthroplasty services and between the 2 patient groups, patient perspectives of waiting times may also be different.
To compare waiting times for initial orthopedic consultation and total hip and knee arthroplasties in rural Ontario (Stratford) and in urban Ontario (London), and to compare patient perspectives of these waiting times, we mailed a survey to all 260 patients who underwent total hip or total knee arthroplasty between June 1, 2000, and June 1, 2001. The survey asked for the length of wait for consultation and for surgery, acceptability of waiting time for surgery, the effect of waiting on health and what an acceptable waiting time would be. Of the 260 surveys mailed 202 (78%) were returned. We reviewed the charts of the respondents to determine the actual waiting times.
The actual waiting times (mean [and standard deviation]) for initial consultation were significantly (p
Notes
Cites: Ann R Coll Surg Engl. 2001 Mar;83(2):128-3311320923
